An electric power converter that converts power between AC power and DC power is known. Such an electric power converter has a stacked body obtained by stacking a semiconductor module with a built-in semiconductor element and a cooler for cooling the semiconductor module (refer to Japanese Patent Application Laid-Open Publication No. 2011-109767, for example).
The semiconductor module has a positive terminal and a negative terminal in which a DC voltage of the DC power source is applied, and an AC terminal connected to the AC load.
Further, the electric power converter has a capacitor for smoothing the DC voltage.
A plurality of the positive terminals is disposed in a line in a stacking direction of the stacked body.
The plurality of the positive terminals and a positive electrode of the capacitor are electrically connected by a positive bus bar.
Similarly, the plurality of the negative terminals is also disposed in a line in the stacking direction.
Then, the plurality of the negative terminals and a negative electrode of the capacitor are electrically connected by a negative bus bar.
The positive bus bar has a plate-like main body portion, a plurality of extended portions parallel to each other extending laterally from the main body portion, and terminal connecting portions extending from the extended portions in a plate-thickness direction of the body portion.
The terminal connecting portions are joined to the positive terminals and are connected to each other.
The negative bus bar also has a similar structure as the positive bus bar has.
The positive bus bar and the negative bus bar are formed by processing single metal plates, respectively.
That is, when manufacturing these bus bars, first, a flat-plate member is formed by pressing (or the like) a single sheet of metal. This flat-plate member has portions that become terminal connecting portions, extended portions, and a main body portion. Between the portions to be the terminal connecting portions and the extended portions of the flat-plate member are not yet bent (not-bent member).
Thereafter, each of the portions to be the terminal connecting portions is bent at a right angle along a bending line positioned between the portion to be the terminal connecting portions and the extended portion, and parallel to an extending direction of the extended portion.
However, in a conventional electric power converter, there is a problem that the length of the extended portion in the stacking direction is likely to be shortened when the pitch of the stacked body is narrowed.
That is, as described above, when manufacturing the bus bar, the not-bent member is formed with the single sheet of metal first.
The portion to be the terminal connecting portion and the extended portion are adjoining in the stacking direction via a slit in the not-bent member.
The portion to be the terminal connecting portion is connected to the positive terminal or the like after bending.
Therefore, in order to ensure a sufficient contacting surface area, it is necessary to ensure the length of this portion in the stacking direction to a certain amount.
Thus, when narrowing the pitch, it is forced to shorten the length of the extended portions in the stacking direction.
As a result, the extended portion becomes elongated, and a parasitic inductance is likely to be increased.
Therefore, a large voltage surge is likely to occur when the semiconductor element is turned on and off.